Biomaterial Database

Characterization of the ultrastructure and the self-assembly of the surface layer of Bacillus stearothermophilus strain NRS 2004/3a. 1986

P Messner, and D Pum, and U B Sleytr

Zentrum für Ultrastrukturforschung, Universität für Bodenkultur, Wien, Austria.

The ultrastructure of the crystalline surface layer (S-layer) of Bacillus stearothermophilus strain NRS 2004/3a has been characterized by electron microscopy supplemented by optical and computer image analysis. The S-layer, composed of glycoprotein subunits, has oblique symmetry, and can be extracted by guanidine hydrochloride. Upon dialysis, this extract produced both flat and cylindrical mono- and double-layer self-assembly products. Optical diffraction analysis of negatively stained preparations showed five types of double-layered assembly products. Computer filtering separated the double-layer complexes and revealed them to be composed of a common monolayer with p2-symmetry (a = 9.4 nm, b = 11.6 nm, and gamma = ca. 78 degrees). By analysis of freeze-dried and heavy metal-shadowed self-assemblies the surface topography and the characteristic "handedness" of the morphological units have been determined. Labeling with polycationic ferritin has shown that each surface of the S-layer possessed a different net charge. The results indicate that S-layers in vivo could prevent autoagglutination of cells.

UI	MeSH Term	Description	Entries
D008562	Membrane Glycoproteins	Glycoproteins found on the membrane or surface of cells.	Cell Surface Glycoproteins,Surface Glycoproteins,Cell Surface Glycoprotein,Membrane Glycoprotein,Surface Glycoprotein,Glycoprotein, Cell Surface,Glycoprotein, Membrane,Glycoprotein, Surface,Glycoproteins, Cell Surface,Glycoproteins, Membrane,Glycoproteins, Surface,Surface Glycoprotein, Cell,Surface Glycoproteins, Cell
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D005613	Freeze Etching	A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.	Etching, Freeze
D001411	Geobacillus stearothermophilus	A species of GRAM-POSITIVE ENDOSPORE-FORMING BACTERIA in the family BACILLACEAE, found in soil, hot springs, Arctic waters, ocean sediments, and spoiled food products.	Bacillus stearothermophilus,Bacillus thermoliquefaciens